Interpretive Handbook

Test
60764 :
Iron/Creatinine Ratio, Random, Urine

Iron is cleared primarily by biliary excretion via the feces. Renal clearance of iron is a secondary and relatively minor route of clearance. Excessive accumulation of iron in iron-overload diseases leads to higher than normal urine concentration of iron, known as hemosiderinuria.

Normal excretion of iron occurs at the rate of approximately 100 mcg/day to 300 mcg/g creatinine. In the event that dietary iron is below minimum daily requirements (<2 mg/g creatinine in females, <1 mg/g creatinine in males), urinary excretion will be less than normal.

Because iron elimination undergoes extreme diurnal variation (serum levels 10 times higher in am than pm), results from random urine specimens can be very misleading and are of limited value.

High concentrations of gadolinium and iodine are known to interfere with most metals tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen must not be collected for 96 hours.